JPS61221246A - Filled polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which gives moldings having excellent coatability after plasma treatment, by blending an inorg. filler and carbon black having a specified average particle size and a specified surface area with a polypropylene resin in a specified ratio. CONSTITUTION:99.5-60wt% polypropylene resin (A) is mixed with 0.5-40wt% inorg. filler (B) (e.g. calcium carbonate or talc). Further, 0.01-0.6pts.wt. carbon black (C) (e.g. furnace black or channel black) having an average particle size of 5-40mmu and a specific surface area of 50-1,100m<2>/g is blended with 100pts. wt. said filled polypropylene resin to obtain the desired filled polypropylene resin compsn. When the surface of a molding obtd. from the compsn. is treated with plasma and coated, a coating film having excellent peel strength, hot water resistance, etc., can be formed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a polypropylene resin composition, and more particularly to a filler-containing polypropylene resin composition whose molded products have excellent paintability after plasma treatment. .

[Prior Art] Polypropylene resin is lightweight, durable, safe, stylish, and economical.

Molded products are widely used in various industrial parts such as automobile parts, but many of them have various inorganic fillers added to improve their rigidity, heat resistance, dimensional stability, etc. They are often colored black or black-like colors in consideration of color tone and weather resistance, but recent market needs include the desire to make them more luxurious by painting them, depending on where they are used. As paint quality increases, it has become essential to provide paintability.

Currently, the coating method for polypropylene resin molded products involves surface treatment of the resin molded products with halogen-containing organic solvents such as trichloroethylene and trichloroethane.
After that, a primer coating and a top coat are often applied, but in order to eliminate the problem of environmental pollution caused by halogen-containing organic solvents and to reduce costs by omitting processes, a method of applying a top coat after surface treatment of the molded product by plasma treatment has been implemented. It has started to be done.

In most cases, the polypropylene resin before painting is
Regardless of the distinction between full-scale painting and partial painting, inorganic,
In many cases, parts are colored with organic colorants or a combination of these, and in particular for parts that will be used outdoors, it is important to take into consideration how they will be used and to improve their weather resistance. It is common to add carbon black or a black pigment mainly composed of carbon black, and for this reason the amount of carbon black added to the polypropylene resin is currently increasing.

[Problems to be Solved by the Invention] However, it has become clear that when a molded product made of polypropylene resin to which a large amount of carbon black has been added is painted after plasma treatment, the paintability is significantly reduced. As a result of extensive research into filler-containing polypropylene resin compositions that have good paintability when painted after plasma treatment, we have found that by specifying the type and amount of carbon black used, the paintability of molded products can be dramatically improved. The present inventors have discovered that the present invention can be improved in terms of performance, and have completed the present invention.

[Means for Solving the Problems] That is, the present invention includes a filler-containing polypropylene resin consisting of at least a polypropylene resin and an inorganic filler, and carbon black, and the filler-containing polypropylene resin contains a polypropylene resin and an inorganic filler. Filler blending ratio is polypropylene resin 139
．． Inorganic filler 0.5 for 5t mass% to 60% by weight
-40% by weight, 0.01 to 0.6 parts by weight of carbon black is blended with 100 parts by weight of the filler-containing polypropylene resin, the average particle size of the carbon black is 5 to 40%, and the specific surface area is This is a filler-containing polypropylene resin composition characterized in that the filler content is 50 to 1100 m''/g.

[Embodiments of the invention] The polypropylene resin used in constructing the filler-containing polypropylene resin composition of the present invention is:
It refers to ethylene-propylene copolymers or copolymers of propylene and other α-olefins, and also includes various polyethylenes, other crystalline resins, and various rubbers (EPR, EPD).
M etc.) and various pl! , 4 parts 1 organic filler, etc. may be added, or if necessary, part or all may be modified with unsaturated carboxylic acid such as maleic anhydride. Of course, the amount of inorganic filler added may be , must be within the scope of the present invention.

The inorganic filler in the present invention is a so-called inorganic filler, and can be in any form such as powder or fiber, and the material includes, for example, calcium oxide, magnesium oxide, calcium hydroxide, hydroxide, etc. Magnesium, aluminum hydroxide, magnesium carbonate, calcium silicate, magnesium silicate, calcium sulfate,
Calcium carbonate, barium sulfate, magnesium sulfate, calcium sulfite, potassium titanate, talc, clay,
Examples include mica, glass, basic magnesium carbonate, and dolomite. These various inorganic fillers may be surface-treated with any coupling agent, surfactant, etc., and such surface treatment contributes to improving the rigidity and impact resistance of the resin composition.

The filler-containing polypropylene resin composition of the present invention is
Carbon black is added to the filler-containing polypropylene resin containing the above polypropylene resin and inorganic filler, and the blending ratio of the polypropylene resin and inorganic filler in the filler-containing polypropylene resin is as follows:
Considering the rigidity, impact resistance, toning properties, paintability, etc. of the resulting resin composition, the polypropylene resin has a rating of 88.5~
The inorganic filler content is preferably in the range of 0.5 to 40% by weight relative to 60% by weight.

If the blending ratio of the inorganic filler is less than 0.5% by weight, the resulting resin composition will have low rigidity, while if it exceeds 40% by weight, the impact resistance will decrease, color matching will become difficult, etc. Due to the moisture contained in the paint, the hot water resistance after painting decreases, making it easier for blistering to occur between the resin layer and the paint film.
Either way, I don't like it.

In addition, carbon black in the present invention includes furnace black, thermal black, channel black, acetylene black, etc., which are generally used to color polypropylene resin black, but they have different color tone, heat resistance, and weather resistance. etc., the average particle size is 5 to 40 mm,
Those having a specific surface area of 50 to 1100 rn'/g are used. Among them, furnace black and channel black are preferable. Of course, these carbon blacks are
Two or more types can also be used in combination.

The amount of carbon black added is 0.1 to 0.6 parts by weight, preferably 0.05 to 0.5 parts by weight, based on 100 parts by weight of the total amount of polypropylene resin and inorganic filler in the filler-containing polypropylene resin. It is necessary that If the amount added is less than 0.01 part by weight, the weather resistance of the resin composition will decrease, and generally used heat resistance and weather resistance stabilizers can be used to improve the weather resistance. It is necessary to use a considerable amount of these stabilizers for parts that require high properties, which not only increases the price, but also causes the stabilizers to stand out on the surface of the molded product after molding, resulting in poor paintability and appearance. It is not practical because it has drawbacks such as deterioration. On the other hand, if the amount added exceeds 0.6 parts by weight, the peel strength of the coating film when the molded product is coated after plasma treatment will be significantly lowered, and blistering will be more likely to occur in the hot water resistance test, which is undesirable.

In addition, the average particle size of carbon black is monodispersity, color tone,
It is necessary that the average particle size be within the above range from the viewpoint of weather resistance, etc. If the average particle size is small, the particles will cause secondary agglomeration and the dispersibility will decrease, and the price will also be high; This will not only worsen the color tone but also reduce weather resistance.
In any case, it is undesirable.The value of the average particle diameter of carbon black shall be measured directly using an electron microscope, and the value of the specific surface area shall be determined from the amount of nitrogen, iodine, etc. adsorbed.・The filler of the present invention In addition to the above-mentioned polypropylene resin, S machine filler, and carbon black, the polypropylene resin composition containing oxidation, which is usually added to polypropylene resin, as necessary, may be used within a range that does not significantly impair the effects of the present invention. Inhibitors, heat stabilizers, ultraviolet absorbers, flame retardants, nucleating agents, organic pigments, etc. may be used alone or in combination.

The filler-containing polypropylene resin composition of the present invention is
The polypropylene resin, inorganic filler, carbon black, and additives listed in 1 above are blended as necessary. Various known means can be used for blending.For example, the present invention may be made into pellets. If you want to obtain a resin composition, mix the above components using a Henschel mixer commonly used in the industry, and then use a single screw extruder, a twin screw extruder such as FGM or ICM, a roll, or a Banbury extruder. It can be easily obtained by kneading using a mixer or the like.

The resin composition thus obtained can be molded into a desired molded article by commonly used molding methods such as injection molding, extrusion molding, and compression molding.

Plasma surface treatment of molded products is carried out by, for example, bringing plasma generated by exciting oxygen, nitrogen, other inert gases, or a mixture of these gases into contact with the surface of the molded product using high frequency, microwave discharge, etc. can be done. The conditions vary somewhat depending on the type of gas, but usually the pressure is 0.1 to 5.
Torr and processing time of about 5 to 600 seconds is appropriate. However, depending on the shape of the molded product, it may be necessary to lengthen the treatment time or change the shape of the treatment tank.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Examples 1 to 5] Ethylene content 8.8% by weight as polypropylene resin
, ethylene-propylene block copolymer (PP-A) with a melt flow index of 8.0 g/10 m1n,
Using talc with an average particle size of 1.3 $ as an inorganic filler, 2,6-sheet tert- Butylphenol 0.0
5 parts by weight, calcium stearate 0.1 part by weight, tetrakis-[methylene-3-(3',5'-di-tert)
-butyl-4'-hydroxyphenyl)propionate 37770.2 parts by weight, bis(2,2,8,8-tetramethyl-4-pipenzyl)sebacate 0.4 parts by weight, 2
-(3-tart-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzenetriazole 0.2
Weight part, average particle size is 18Q, specific surface area is 200 m''
/g (hereinafter referred to as carbon black A) or an average particle size of 14Q and a specific surface area of 280 m
”/g of channel black (hereinafter referred to as carbon black B) was blended in the amounts shown in Table 1. After mixing each blend with a Henschel mixer,
A resin composition of the present invention was pelletized using a 40 m-φ extruder set at ℃. Each of the obtained resin compositions was molded by injection molding, and a test piece for painting (80
X180

Each of these test pieces was subjected to plasma treatment under the following conditions, then coated with B-liquid urethane topcoat to a film thickness of 50 μs, dried at 90°C for 40 minutes, and then heated at room temperature. A coated product was obtained by leaving it for 48 hours.

For each of the thus obtained coated articles, the coating film of the coated article was cut with a cutter to a width of 1. An incision was made in the Oc layer and the coating film was tested at 180' using an Instron tensile tester.
The peel strength was measured and each of these coated products was
The paintability was evaluated by immersing the film in warm water at 0.degree. C. and visually determining the state of the film after 240 hours.

The results are shown in Table-1.

Plasma processing equipment; Toshiba microwave plasma processing equipment (TMZ-2028N) 2) Processing gas: Oxygen 3) Processing time: 30 seconds 4) Gas pressure: 1.0 tart 5) Gas flow rate
; 480 cc/layer 1n6) Microwave output;
1500W [Examples 6 to 7] Tests were conducted in the same manner as in Example 1, except that talc in Example 1 was replaced with calcium carbonate with an average particle size of 1.9Q and barium sulfate with an average particle size of 1.2Q. The results are shown in Table 1.

[Example 8] Same as Example 1, except that polypropylene homopolymer (PP-8) with a melt flow index of 7.5 g/10 in. was used instead of PP-A used in Example 1. The results obtained are shown in Table 1.

[Example 9] The blending amounts of pp-a and talc in Example 8 were changed to 70 parts by weight and 15 parts by weight, respectively, and an ethylene-propylene copolymer having a propylene content of 27% by weight and a Mooney viscosity of 70 at 100°C was used. Combined rubber (EPR-A) 1
The test was carried out in the same manner as in Example 8, except that 5 parts by weight was added, and the obtained results are shown in Table 1.

(Example 10) The test was conducted in the same manner as in Example 1, except that the amounts of PP-A and talc were changed to 85 parts by weight and 5 parts by weight, respectively, and the obtained results are shown in Table 1. .

[Examples 11 to 13] The carbon black in Example 1 was used as a carbon blur with an average particle size of 6 mm and a specific surface of 11000 m'/g, Ri C1.
The test was carried out in the same manner as in Example 1, except that carbon black D with an average particle size of 35 mm and a specific surface area of 800 m''/g was used, and the amount added was as shown in Table 1, and the obtained results are shown in Table 1. .

[Comparative Examples 1 to 4] Tests were conducted in the same manner as in Example 1, except that the amount of carbon black added in Examples 1, 3, 8, and 9 was changed to 1.0 parts by weight, and the obtained results are shown in Table 1. Shown below.

As is clear from the above Examples and Comparative Examples, the resin composition of the present invention has excellent coating peel strength and water resistance, and exhibits extremely good paintability.

[Effects of the Invention] As explained above, the filler-containing polypropylene resin composition of the present invention makes it possible to obtain molded articles with extremely good paintability after plasma treatment.

Procedural amendment (voluntary) March 28, 1981

Claims (1)

[Claims] (1) a filler-containing polypropylene resin consisting of at least a polypropylene resin and an inorganic filler;
carbon black, and the blending ratio of the polypropylene resin and inorganic filler in the filler-containing polypropylene resin is 99.5% by weight to 6% by weight of the polypropylene resin.
The amount of inorganic filler is 0.5-40% by weight relative to 0% by weight, and 0.01-0.6 parts by weight of carbon black is blended with 100 parts by weight of the filler-containing polypropylene resin. Average particle size is 5~40mμ
, a filler-containing polypropylene resin composition having a specific surface area of 50 to 1100 m^2/g.